The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component that can be created using a fabrication process) has decreased.
The fabrication of IC devices typically involves a passivation process, in which a passivation structure is formed to protect the electronic components inside the IC devices from moisture, dust, and other contaminant particles. Post passivation interconnect (PPI) devices may be used to establish electrical connections between these electronic components inside the IC device and external devices. However, conventional IC devices often have poor PPI distribution uniformity. In other words, the PPI devices may have a high population density in some areas of an IC device while having a low population density in other areas of the IC device. The lack of PPI uniformity may adversely affect electrical performance and packaging reliability of the IC device.
Therefore, while existing IC passivation structures are generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.